The present invention involves an in-the-ear monitoring instrument having the form factor of a hearing aid. Most hearing aids include an earmold which is inserted and retained in the canal of the ear of the user. The earmold may contain the electronics of the hearing aid, including the receiver, or may be connected to the electronics, which are outside the canal of the ear, by a tube. The earmold desirably fits comfortably in the ear and is formed in a manner that it is readily retained in the canal of the ear. Retention of the earmold in the ear canal may be accomplished by friction and/or mechanical locking. Friction is created by radial pressure of the earmold on the wall of the canal. The more pressure, the greater is the retention force. However, friction is also dependent on lubricants between the earmold and the wall of the canal. The presence of cerumen (ear wax), perspiration or water significantly reduces friction retention. Therefore, mechanical locking is the primary means by which most hearing aids are retained in the ear. For mechanical locking, the earmolds are molded to fit the complex shape of the ear canal. These complex interlocking shapes hold the hearing aid in place without relying on friction so that they are not susceptible to the loosening caused by forces which tend to dislodge the hearing aid. However, the making of these complex interlocking shapes is a laborious, inaccurate and time consuming process which often requires the user to make several visits to the audiologist or dispenser before an earmold with a secure fit can be made. This is not only time consuming, but also greatly increases the cost of the hearing aid.
Two of the more recent attempts at commercializing preformed earmolds are shown in U.S. Pat. No. 4,870,688 to B. Voroba et al., issued Sep. 26, 1989, entitled MASS PRODUCTION AUDITORY CANAL HEARING AID, and U.S. Pat. No., 5,002,151 to R. J. Oliveira et al., issued Mar. 26, 1991, entitled EAR PIECE HAVING DISPOSABLE, COMPRESSIBLE POLYMERIC FOAM SLEEVE. The earmold shown in the patent to Oliveira et al. uses a compressible retard recovery foam that can be compressed and then inserted into a person's ear, and allowed to recover to fill into the canal. This earmold is held in only by friction. Also, the earmold is connected to the electronics by a tube which has the tendency to pull on the earmold frequently and thus dislodge it. For this reason, these devices are limited to short trial periods.
The hearing aid shown in the patent to Voroba et al. uses a soft polymeric material in solid form. The earmold is designed to utilize both friction and mechanical locking. However, the earmold contains the electronics and, so, the weight and cantilever of the hear aid tends to dislodge the earmold over time. To support the cantilever, the Voroba et al. earmold is designed to fill in the canal and the concha. However, making a generic earmold which fits well both in the canal and in the concha is difficult. Also, the earmold of Voroba et al. is designed for several years of use, requiring that is be made of a harder material.
The use of a generic earmold and casing could also have applications for an in-the-ear monitoring instrument.
Monitoring the vital health signs of a patient typically requires excessive time of medical personnel, or the patient being inconvenienced by being connected by wires to bulky monitoring equipment. For example, in a hospital setting, a nurse has to travel from patient-to-patient in order to determine such vital health signs as temperature and pulse. These account for a substantial amount of the nurse's time and do not provide continuous data. Continuously monitoring vital health signs may require the use of cumbersome and expensive equipment, and may cause the patient discomfort and inconvenience because this equipment has to be connected to the patient and thereby limiting the patient's mobility. Both the time expended by medical personnel in obtaining vital health signs of patients, as well as the bulky equipment required, can account for a substantial cost in caring for patients.
It would be desirable to have a simple low cost in-the-ear monitoring instrument which uses a generic earmold and casing that fits securely and comfortably in ear canals of various sizes and shapes. This monitoring instrument continuously or continually monitors a patient's vital health signs and transmits these vital health signs to a remote monitoring unit without the need for the patient being physically connected to the monitoring unit. It would also be most desirous if such monitoring instrument were relatively non-intrusive to the patient and if the monitoring instrument were relatively inexpensive with regard to both the structure of its components and its method of manufacture. In addition, it would be desirable for such a monitoring instrument to have an integral power source and to be so inexpensive that it could be disposed of after its power source expires.